Josephson current through a precessing classical spin

Sofian Teber (1) , Cecilia Holmqvist (2) , Manuel Houzet (3) , Denis Feinberg (4) , Mikael Fogelstrom (5)

1 LPTHE - Laboratoire de Physique Théorique et Hautes Energies
2 Applied Quantum Physics Laboratory, MC2
3 INAC - Institut Nanosciences et Cryogénie
4 NEEL - ThQC - Théorie Quantique des Circuits
5 Chalmers University of Technology [Göteborg]

A study of the dc Josephson current between two superconducting leads in the presence of a precessing classical spin is presented. The precession gives rise to a time-dependent tunnel potential which not only implies different tunneling probabilities for spin-up and spin-down quasiparticles, but introduces also a time-dependent spin-flip term. We provide an exact general analytic solution for the out-of-equilibrium steady-state permanent current between two spin-singlet superconductors as a function of the superconducting phase difference, the precession frequency and for arbitrary junction transparency. As an application we focus on the effects of the spin-flip term alone and show that the magnitude and nature of the Josephson current are indeed strongly affected by the precession of the classical spin.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Sofian Teber, Cecilia Holmqvist, Manuel Houzet, Denis Feinberg, Mikael Fogelstrom. Josephson current through a precessing classical spin. Physica B: Condensed Matter, 2009, 404 (3-4), pp.527-529. ⟨10.1016/j.physb.2008.11.053⟩. ⟨hal-00528898⟩